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Groups > linux.kernel > #1241525 > unrolled thread
| Started by | Vinod Koul <vinod.koul@intel.com> |
|---|---|
| First post | 2015-10-07 16:00 +0200 |
| Last post | 2015-10-09 17:30 +0200 |
| Articles | 3 — 2 participants |
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Re: [PATCH 1/2] dmaengine: hdmac: factorise memset descriptor allocation Vinod Koul <vinod.koul@intel.com> - 2015-10-07 16:00 +0200
Re: [PATCH 1/2] dmaengine: hdmac: factorise memset descriptor allocation Maxime Ripard <maxime.ripard@free-electrons.com> - 2015-10-07 19:40 +0200
Re: [PATCH 1/2] dmaengine: hdmac: factorise memset descriptor allocation Vinod Koul <vinod.koul@intel.com> - 2015-10-09 17:30 +0200
| From | Vinod Koul <vinod.koul@intel.com> |
|---|---|
| Date | 2015-10-07 16:00 +0200 |
| Subject | Re: [PATCH 1/2] dmaengine: hdmac: factorise memset descriptor allocation |
| Message-ID | <qgXqb-6Da-29@gated-at.bofh.it> |
On Thu, Oct 01, 2015 at 04:52:37PM +0200, Maxime Ripard wrote:
> +static struct at_desc *atc_create_memset_desc(struct dma_chan *chan,
> + dma_addr_t psrc,
> + dma_addr_t pdst,
> + size_t len)
> +{
> + struct at_dma_chan *atchan = to_at_dma_chan(chan);
> + struct at_desc *desc;
> + size_t xfer_count;
> +
> + u32 ctrla = ATC_SRC_WIDTH(2) |
> + ATC_DST_WIDTH(2);
why is this over two lines :)
> + u32 ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN |
> + ATC_SRC_ADDR_MODE_FIXED |
> + ATC_DST_ADDR_MODE_INCR |
> + ATC_FC_MEM2MEM;
> +
> + xfer_count = len >> 2;
> + if (xfer_count > ATC_BTSIZE_MAX) {
> + dev_err(chan2dev(chan), "%s: buffer is too big\n",
> + __func__);
> + return NULL;
> + }
This is fine, but this is driver limitation. We should really split the
txn to multiple descriptors here..
> @@ -914,46 +953,26 @@ atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
> return NULL;
> }
>
> - xfer_count = len >> 2;
> - if (xfer_count > ATC_BTSIZE_MAX) {
> - dev_err(chan2dev(chan), "%s: buffer is too big\n",
> + vaddr = dma_pool_alloc(atdma->memset_pool, GFP_ATOMIC, &paddr);
Mostly people use _zalloc variant, any reason why you don't want that
--
~Vinod
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| From | Maxime Ripard <maxime.ripard@free-electrons.com> |
|---|---|
| Date | 2015-10-07 19:40 +0200 |
| Message-ID | <qh0R4-3eS-7@gated-at.bofh.it> |
| In reply to | #1241525 |
[Multipart message — attachments visible in raw view] — view raw
Hi Vinod,
On Wed, Oct 07, 2015 at 02:54:13PM +0100, Vinod Koul wrote:
> On Thu, Oct 01, 2015 at 04:52:37PM +0200, Maxime Ripard wrote:
>
> > +static struct at_desc *atc_create_memset_desc(struct dma_chan *chan,
> > + dma_addr_t psrc,
> > + dma_addr_t pdst,
> > + size_t len)
> > +{
> > + struct at_dma_chan *atchan = to_at_dma_chan(chan);
> > + struct at_desc *desc;
> > + size_t xfer_count;
> > +
> > + u32 ctrla = ATC_SRC_WIDTH(2) |
> > + ATC_DST_WIDTH(2);
>
> why is this over two lines :)
>
> > + u32 ctrlb = ATC_DEFAULT_CTRLB | ATC_IEN |
> > + ATC_SRC_ADDR_MODE_FIXED |
> > + ATC_DST_ADDR_MODE_INCR |
> > + ATC_FC_MEM2MEM;
> > +
> > + xfer_count = len >> 2;
> > + if (xfer_count > ATC_BTSIZE_MAX) {
> > + dev_err(chan2dev(chan), "%s: buffer is too big\n",
> > + __func__);
> > + return NULL;
> > + }
>
> This is fine, but this is driver limitation. We should really split the
> txn to multiple descriptors here..
Both these things are actually just copy from the previous code.
I can probably fix the first style issue in this patch, but splitting
the memset descriptors should go in a separate patch.
>
> > @@ -914,46 +953,26 @@ atc_prep_dma_memset(struct dma_chan *chan, dma_addr_t dest, int value,
> > return NULL;
> > }
> >
> > - xfer_count = len >> 2;
> > - if (xfer_count > ATC_BTSIZE_MAX) {
> > - dev_err(chan2dev(chan), "%s: buffer is too big\n",
> > + vaddr = dma_pool_alloc(atdma->memset_pool, GFP_ATOMIC, &paddr);
>
> Mostly people use _zalloc variant, any reason why you don't want that
Not necessarily, but I don't need zeroed memory either, since I
overwrite the content right after the allocation.
Maxime
--
Maxime Ripard, Free Electrons
Embedded Linux, Kernel and Android engineering
http://free-electrons.com
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| From | Vinod Koul <vinod.koul@intel.com> |
|---|---|
| Date | 2015-10-09 17:30 +0200 |
| Message-ID | <qhHMm-63K-25@gated-at.bofh.it> |
| In reply to | #1241707 |
On Wed, Oct 07, 2015 at 06:33:17PM +0100, Maxime Ripard wrote: > > This is fine, but this is driver limitation. We should really split the > > txn to multiple descriptors here.. > > Both these things are actually just copy from the previous code. > > I can probably fix the first style issue in this patch, but splitting > the memset descriptors should go in a separate patch. That sounds fine -- ~Vinod -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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